Refrigerating control means



Oct. 10, 1933.

J. L. SHRODE 1,929,523

REFRIGERAT I NG CONTROL MEANS FilecLApril 11, 1950 2 Sheets-Sheet l &

INVEN TOR L/0/77V L. 5/?005 BY W Q ,4 TTORNEYJ" Oct. 10, 1933. J. L,SHRODE 1,929,523

REFRIGERAT ING CONTROL MEANS Filedjpril 11, 1930 2 Sheets-Sheet 2 km D31N VEN TOR L/OHN L. SHAODE A TTORN Y Patented Oct. 10, 1933REFRIGERATING CONTROL MEANS John L. Shrode, University City, Mo.,assignor to Alco Valve Company, St. Louis, Mo.,

ration of Missouri Application April 11, 1930. Serial No. 443,593-

9 Claims.

This invention relates to improvements in refrigerating control means,and particularly to an improved float-actuated switch assembly asemployed for purposes of controlling a flow of liquid refrigerant.

An object of the invention may be generally stated as the attainment ofan improved regulation and control of the quantity and flow of liquidrefrigerant in the expansion portions of a refrigerating system.

Another object is to produce a more reliable and more readily responsiveautomatic control of the delivery of refrigerant to the low pressureside of a refrigerating system.

A still further object'is attained in a novel combination of switchingmeans for refrigerant flow control, disposed within the low pressureside of the system and controllable by a liquid level therein, withthermally responsive means, such as a thermostat, in the same controlcircuit.

A further object of the invention is found in the improved arrangementand combination of enclosed parts constituting a float actuated switchin an electric circuit including translating means for control of avalve in a liquid line of the high pressure portion of a refrigeratingsystem.

Yet another object of the invention is attained in an improvedstructural arrangement of parts comprising a float-actuated switchassembly, whereby such assembly may, as a unit, be installed within, orremoved from the refrigerating system for purposes of repair orreplacement of parts, with a minimum, or no interruption of use of thesystem. Further objects and advantages of the invention will appear fromthe following detailed descriptionand drawings of a presently preferredexecutional embodiment of the invention. In the drawings:

Fig. 1 is a sectional elevation through a preferred form of float switchtank, and Fig. 2 is a schematic or diagrammatic representation of arefrigerating system equipped according to the present improvements.

Referring now by reference characters to the drawings, the system shownin the diagram of Fig. 2 includes a compressor A, the discharge or high.pressure side of which is connected as by a pipe B to a condenser unitC which may be of any usual form, and which may consist of a condenserof usual type, or some combination of condenser and receiver. The unit Cis arranged for delivery of the liquid refrigerant such as ammonia,through a pipe D, to an expansion unit E. It will be understood that inthe present instance, the

expansion unit E may consist of one or any suitable number of coolingcoils disposed in the same, or different locations, the present systemof control being well adapted for a multiple low-side system embodying apluralityof freezing units. It is preferred in such case to employ asingle liquidreceiving portion whose inlet is supplied by the pipe D.The outlet from the expansion unit is connected to a pipe F, directed tothe inlet side of the compressor A, and thus the refrigerant completes acircuit of the system.

For purposes of controlling the flow of liquid from the unit C throughpipe D and into the expansion unit, I provide an electro-magneticstop-valve G in the line D, this valve being of any suitable type and soarranged that the valve element is lifted or opened to permit flowthrough the pipe D when the electro-magnetic structure of the valve isenergized, as hereinafter described. Interposed in the same line, andbeyond the magnetic valve, is.a flow-limiting valve H, which may be ofany suitable type, and which is, by preference, provided as a means forestablishing the desired maximum flow of refrigerant through the pipe D.

There is disposed, by preference adjacent the expansion unit, a floatswitch tank.-I, which is connected to the liquid-containing portion ofthe expansion unit by means of a pipe J, arranged,

normally, to maintain the same level of liquid in the float tank I, asin the expansion unit E. 1 There is further provided a vent tube Khaving its inlet in the upper portion of the float tank, and itsopposite end likewise in the upper portion of the liquid chamber of theexpansion unit.

The vent tube serves to maintain a uniform vapor pressure in each of thetanks E and I, above their respective bodies of liquid.

There is provided by preference and shown diagrammatically at L, athermostat in the nature of any usual form of thermally-responsivecircuit closing means preferably arranged to close the circuithereinafter referred to upon attaining approximately a given temperaturein the refrigerated enclosure, the device being, by preference and asknown in the art, adjustable to different settings according to thedifferent refrigerating temperatures desired.

The electrical control-circuit arrangement employed in the presentexample is thought to be apparent from Fig. 2, but may briefly bedescribed as consisting of a feeder circuit having as legs theconductors 5 and 6, the side 5 of the line, according to the presentshowing being connected directly to the magnetic stop-valve G,

and the side 6 being provided with switching means indicated as thethermostat L and with additional switching means within the float tank,as hereinafter described, thence connected to the opposite side of thestop valve G.

Referring now more particularly to Fig. 1, it will be seen that thefloat tank I is, by preference, of upright, cylindrical form and maybeof cast construction, provided with a single removable end plate or headmember 7 which may be secured as by bolts, (not shown) to the flangedupper portion of-the tank I. Centrally disposed at the opposite ends ofthe tank I are a pair of bosses 8 provided with central sockets or guideways for slidably receiving the opposite ends of a float rod 9, to whichis aiflxed a float 10, preferably of hollow metallic construction. Therod 9 is, in the present arrangement, provided with a slotted aperture11 adapted to accommodate in lostmotion engagement, a switch pin 12.This pin extends from one end of a rocking lever 13, supported formovement about a pin 14 carried for example, by the wall of the casingI. The

plate 13 serves to carry, in fixed relation, a tube 15 containing asmall quantity of mercury, one end of the tube being provided withspaced interior terminals 17 to respective ones of which are connectedconductors 18, each constituting a portion of the line 6 as it appearsexternally of the float tank. Entrance bushings 19 are by preferencethreadedly mounted in the head portion 7 of the tank, these bushingsbeing formed preferably of insulating material. Extending centrallythrough each of the bushings 19 is a metal sleeve 20 which servesclosely to engage the outside of the conductor in a manner to constitutea fluid-tight joint.

While the operation of the device constructed according to thisinvention may be fully apparent from' the preceding description of itsparts, it

may be briefly summarized for sake of completeness, as follows: I

The operation of compressor A, together with the condensing action ofthe unit C, creates a flow of liquid refrigerant through the pipe D,into the expansion unit E, as determined, of course, by the opening orclosing of the electromagnetic stop valve G, and subject to anyrestriction of flow that may be imposed by adjustment of valve H. Theeffect is obviously to maintain liquid refrigerant at certain levels inthe expansion unit E, and by means of the pipes J and K at correspondinglevels in the float tank I. Under the influence of raising or loweringthe level of liquid in tank I, the float 10 and float rod 9 are raisedand lowered. With a certain decrease in volume of liquid in tank I, asthe liquid is vaporized and subjected to expansion in the unit E,

- the float 10 is depressed by its own weight so that the upper portionof slot 11 impinges against pin .require further expansion in, andcooling action by the unit E, the thermostat L will move to closedposition. The circuit having previously been closed across terminals 17,the electro-magnetic valve C will be energized and opened, permittingflow of refrigerant to the expansion unit. As this-flow continues and asfreezing progresses,

the level of liquid will rise in the cooling unit E, and correspondinglyin the tank I. The pin 12 engaging the lower extremity of the slot 11will then tend to raise the corresponding end of the plate frame 13 totilt the mercury switch to somewhat beyond horizontal position, movingthe mercury by gravity away from the terminals 1'1 to the opposite endof the tube, causing the pin 12 again to engage the upper or outer endof the slot 11 and leaving the switch in open position, thusdeenergizing the electro-magnetic valve, regardless of whetherthermostat L is in open or closed position.

Obviously the system and control arrangement is operative without theprovision of thermostat L, which may be omitted or shorted out ifoperating conditions are such that the opening'or closing of valve G maybe effected solely in accordance .with the quantitative flow of liquidto the expansion unit.

I am aware of the fact that it is well known to employ mercury typeswitches in control circuits of various types; further that it has beenknown to use a float for purposes of regulating a flow or supply ofliquid refrigerant. So far as I am presently aware, however, there hasnot previously been employed the present combination of a mercury typeswitch directly float-actuated according to rise and fall of liquidlevel, and in a common container. The certainty of control and knownadvantages of a mercury type switch provide, according to the presentsystem, an improved regulation of operation and more reliable automaticcontrol than has heretofore been attained in systems of this type. Thepresent arrangement of float switch assembly within a single containereliminatesall glands, stuffing boxes, packing, etc., incident tolocating the float inside and the switch outside of the liquid chamber.Except for the disadvantage of necessarily shutting down the system forswitch replacements or repairs, the float switch assembly may be mountedin the expansion unit itself, instead of employing the preferredarrangement of a separate float ank.

The fluid tank assembly including the structural combinations described,possesses distinct advantages from the point of view of service accessand ease of installation. It will appear that the present arrangementprovides a double control, through magnetic valve G, over the flow ofrefrigerant into the low pressure side of the system, the valve beingresponsive to cut off the flow of refrigerant according to the openposition of either the thermosat L or the tank switch assembly.

From the point of view of convenience of access for anypurpose it willappear that the entire float valve assembly may be removed from the headof the tank I simply by removing the bolts 135 (not shown) securing thehead or cover '1 to the tank, and withdrawing the entire assembly as aunit from the tank.

To the end of simplifying replacements or repairs it is my preference toprovide valves (not 140 shown) in the pipes J and K, which valves may beclosed to render the removal of the entire float tank a matter of but afew minutes time and without necessitating any interruption of thesystem whatever. The arrangement presently described 145 has been foundto be durable and practical, and

to be particularly adapted for use in multiple refrigerant, a float.assemblyinsaid chamber, including a switch having its operating partssealed in said chamber and its terminals out "of contact with'therefrigerant, said switch adapted for relating themovements of said floatfor controlling liquid .ammonia supply to said chamber, a switchconductor extending-throughia chamber wall, and a combined sealingand-insulating bushing for said conductor, secured to said wall.

2. Refrigerating" apparatus including a compressor, a condenser, anexpansion unit, an elec'- .trically actuated valve for controlling aflow of' refrigerant to the expansion unit,v a chamber associated withthe expansion unit; a valve-circuit control switch, the'movable elementsof'which are disposed entirelywithin; said chamber, switch conductorsextending, therefrom through a wall of said chamber, said; switcharranged for automaticallycontrolling the energization of said valve,responsively'to; the" quantitative flow of refrigerant from thecondenser =into=said expansion unit, and insulating means s'abon't theswitch elements and portionsof the conductors, arranged to sealsaidelements and conductor portions against contact with the,refrigerant. "3,-R efrigerating apparatus including. a comvpressor, acondenser,an expansionunit, an elec trically actuated valve forcontrolling aflow of refrigerant to :the expansion unit, a chambercommunicatingwith; the expansion unit, a switch disposed in said'chamberabovehthe maximum 1 level of iefrigerahhthereih, and arranged incirI-cuit with said;electrically,- actuated valve, connectionsfromsaidswitch, througha wall of the chamber, to said valve,,fluid-tight bushings for said connections constructed'to insulate theconnections from said wall; and toseal the chamber about theconnections, anda float in said chamber, operatively related to saidswitch.

4. Refrigerating apparatus including in com- I 7 binatiomacoznpressor,a-condenser, an expansion unit, an electrically actuatedvalve forcontrolling a flcwof liquid refrigerant to the expansion unit, a chambercommunicating with the expansion,

a float-actuatedswitch assembly having switch terminals out ofcontactfwith the refrigerant, the switch part's'all beingidis p'osed foroperation entirely within said chamber, and arranged for controllingsaid valve, connections from said switch to saidvalve, andinsulating,

- bushings formin'ga'fluid-tightsealforsaid connections, wherethey-extend through a wall of 1 Isaidchamber.

' pressor, a condenser, an expansion unit, an elec- 5. Arefrigerationsystem including a comtrically-a'ctuated valve for controlling a flow ofthrough the enclosing, structure, a float, a rod operatively associatingthe float and switch, and

opening, a float and a mercury switch irisaid of the container,

- the assembly being removable as removal of said wall portion.

refrigerant to the expansion unit, a chamber associated with theexpansion unit and containing aliquid refrigerant, a switch ofconductingliquid type mounted for actuation within said chamber and incircuit relation for controlling said valve, thermal-responsive means insimilar circuit relation, for controlling said valve according torefrigerating temperatures, and means for actuating said switchresponsively to a change in liquid'level in said chamber.

6. In a refrigerating system, an expansion unit, an electricallycontrolled refrigerant valve,

a switch assemblyincluding a pressure container therefor connected nearits opposite ends with the expansion unit, and thereby subjected to thepressures within the expansion unit, a mercm'y switch and conductorsthereto, disposed entirely within said container, the conductorsextending outwardly through the container wall, a float operativelyconnected with the switch, the switch arranged for relating the positionof said valve to the position of the float, and combined insulating andpressure-sealing members for the conductors, threadedly carried by thecontainer wall.

. 7. In a refrigerating system, a compressor, a condenser, an expansionunit, an electrically energized valve arranged to control flow ofrefrigerant to the expansion unit, a switch assembly for controllingsaid. valve and arranged for actuation responsively to the quantity ofrefrigerant insaid expansion unit, said assembly being sealed influid-tight relation in a part of the expansion unit, and including aconducting-liquid type switch, switch leads extending from the switchcombined insulating and sealing members for the ,switch leads, disposedbeyond the liquid zone within ,theexpansion unit. I

8. A refrigerant control switch assembly inerant, having an inletopening and an outlet container, means-.-'relating the movement of thefloat for actuating the switch, conductors from the switch to pointswithout the container, and

eluding a fluid-tight containerfor liquid reirigconductor bushingsformed of an insulating ma j terial,1and secured in sealing relation tothe-walld'uctors. i Y v 9. In combination in an ammonia refrigeratingsystem, a control-switch assembly including av fluid-tight float tankadapted to be subjected to 7 internal pressure other than atmospheric,said} tankflhavinga liquid inlet passage and a vent 13o passage, amercury switch in said tank, conductor-bushings of insulating material,said bushings being mounted in fluid sealing relation in avail of thecontainer above the liquid levels therein, conductors from said switchto a point outside of said tank, and a float having operative connectionwith said switch, said tank having aremovable wallportion, the operativeportions of a-unit upon Jorm L. SHRODE.

and aboutjthe associatedcon-

